1. Field of the Invention
This invention relates to a single-lens reflex camera having a flexible printed circuit board disposed between a pentagonal prism and an upper cover thereof.
2. Description of the Prior Art
As a result of the automation of cameras and the application of electronics to cameras, integrated circuit chips and circuit elements provided on a single piece of flexible printed circuit board are now used in cameras. Generally, in single lens reflex cameras, such a flexible printed circuit is disposed between the pentagonal prism and the upper cover of the camera, as disclosed in U.S. Pat. No. 3,846,805.
Generally, a light sensitive element may be arranged around an ocular and mounted on a flexible printed circuit board by one of two methods. In one method, the light sensitive element is mounted directly on the flexible printed circuit board while, in the other method, the light sensitive element is indirectly mounted on the flexible printed circuit board.
In the system where the light sensitive element is mounted directly on a flexible printed circuit board, the light sensitive element is secured to an extended part or section of the flexible printed circuit board; and the fore end of the extended part of the flexible printed circuit board on which the light sensitive element is mounted is carried by a light measuring holder which disposes the light sensitive element in the vicinity of the ocular. However, during manufacture, there is difficulty in mounting the light sensitive element in such a manner. Specifically, in mounting the light sensitive element directly on the fore end of the extended part of a flexible printed circuit board, when the light sensitive element is inserted into the light measuring holder, the extended part of the circuit is too soft and the light sensitive element on the fore end thereof is not optimally positioned for inserting it into the light measuring holder. This may result in the need to search for the fore end of the extended part of the flexible printed circuit board and take it out from a narrow limited space within the camera before the light sensitive element is inserted into the light measuring holder. Also, even after the light sensitive element is inserted into the holder, it is not easy to set it in place because of the softness of the extended section.
In addition to these problems, light measuring integrated circuit chips or bodies have recently combined the light sensitive element with an amplifier in an integrated circuit. Since the integrated circuit is provided with the amplifier, the number of terminals thereof increases. It has been difficult to contact many terminals from both ends of the circuit body with wires that do not cross each other over the extended part. Moreover, since it is necessary to have many wires arranged over the extended part, the extended part must have a greater width. The wide extended part makes it more difficult to mount the light sensitive element onto the light measuring holder, because the former may block view finder light coming from a pentagonal prism, and this must be prevented.
Attempts have been made to facilitate manufacturing process by minimizing these difficulties. One known method involves mounting the light sensitive element indirectly on the flexible printed circuit board. In this method, the light sensitive element is mounted on an unbendable or inflexible hard board. The hard board is attached to an extended part of a flexible printed circuit board. Then, a light measuring holder which is in a given position close to an ocular is arranged to guide and hold this hard board. This method certainly facilitates the mounting and insertion of the light sensitive element into the light measuring holder. However, the problem of preventing the extended part from blocking light coming from the view finder still remains unsolved by this method. Besides, this method calls for mounting of a hard board on the flexible printed circuit board and thus not only causes increase in the number of parts but also requires additional steps in the manufacture.
An object of this invention is to improve cameras.
Another object of the invention is to avoid the aforementioned disadvantages.